xref: /netbsd/lib/libc/locale/mbsrtowcs.3 (revision c4a72b64)
1.\" $NetBSD: mbsrtowcs.3,v 1.4 2002/10/01 17:02:57 wiz Exp $
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3.\" Copyright (c)2002 Citrus Project,
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27.Dd February 4, 2002
28.Dt MBSRTOWCS 3
29.Os
30.\" ----------------------------------------------------------------------
31.Sh NAME
32.Nm mbsrtowcs
33.Nd converts a multibyte character string to a wide character string \
34(restartable)
35.\" ----------------------------------------------------------------------
36.Sh LIBRARY
37.Lb libc
38.\" ----------------------------------------------------------------------
39.Sh SYNOPSIS
40.Fd #include \*[Lt]wchar.h\*[Gt]
41.Ft size_t
42.Fn mbsrtowcs "wchar_t * restrict pwcs" "const char ** restrict s" "size_t n" \
43"mbstate_t * restrict ps"
44.\" ----------------------------------------------------------------------
45.Sh DESCRIPTION
46The
47.Fn mbsrtowcs
48converts the multibyte character string indirectly pointed by
49.Fa s
50to the corresponding wide character string, and stores it to the
51array pointed by
52.Fa pwcs .
53The conversion stops due to the following reasons:
54.Bl -bullet
55.It
56The conversion reaches a null byte.
57In this case, the null byte is also converted.
58.It
59The
60.Fn mbsrtowcs
61has already stored
62.Fa n
63wide characters.
64.It
65The conversion encounters an invalid character.
66.El
67.Pp
68Each characters will be converted as if
69.Xr mbrtowc 3
70is continuously called.
71.Pp
72After conversion,
73if
74.Fa pwcs
75is not NULL pointer,
76the pointer object pointed by
77.Fa s
78is NULL pointer (if the conversion is stopped due to reach a null byte)
79or the first byte of the character just after the last character converted.
80.Pp
81If
82.Fa pwcs
83is not null pointer and the conversion is stopped due to reach
84a null byte, the
85.Fn mbsrtowcs
86places the state object pointed by
87.Fa ps
88to an initial state after the conversion is taken place.
89.Pp
90The behaviour of the
91.Fn mbsrtowcs
92is affected by LC_CTYPE category of the current locale.
93.Pp
94There are special cases:
95.Bl -tag -width 012345678901
96.It "s == NULL || *s == NULL"
97undefined (may causes the program to crash).
98.It "pwcs == NULL"
99The conversion is taken place, but the result wide character string
100is discarded.
101In this case, the pointer object pointed by
102.Fa s
103is not modified and
104.Fa n
105is ignored.
106.It "ps == NULL"
107The
108.Fn mbsrtowcs
109uses its own internal state object to keep the conversion state,
110instead of
111.Fa ps
112mentioned in this manual page.
113.Pp
114Calling any other functions in the
115.Lb libc
116never change the internal
117state of the
118.Fn mbsrtowcs ,
119that is initialized at startup time of the program.
120.El
121.\" ----------------------------------------------------------------------
122.Sh RETURN VALUES
123The
124.Fn mbsrtowcs
125returns
126.Bl -tag -width 012345678901
127.It 0 or positive
128The value returned is the number of elements stored to the array pointed by
129.Fa pwcs ,
130except for a terminate null wide character (if any).
131If
132.Fa pwcs
133is not null and the value returned is equal to
134.Fa n ,
135the wide character string pointed by
136.Fa pwcs
137is not null terminated.
138If
139.Fa pwcs
140is a null pointer, the value returned is the number of elements to contain
141the whole string converted, except for a terminate null wide character.
142.It (size_t)-1
143The array indirectly pointed by
144.Fa s
145contains a byte sequence forming invalid character.
146In this case, the
147.Fn mbsrtowcs
148sets errno to indicate the error.
149.El
150.\" ----------------------------------------------------------------------
151.Sh ERRORS
152The
153.Fn mbsrtowcs
154may causes an error in the following case:
155.Bl -tag -width Er
156.It Bq Er EILSEQ
157The pointer pointed by
158.Fa s
159points an invalid or incomplete multibyte character.
160.It Bq Er EINVAL
161.Fa ps
162points an invalid or uninitialized mbstate_t object.
163.El
164.\" ----------------------------------------------------------------------
165.Sh SEE ALSO
166.Xr mbrtowc 3 ,
167.Xr mbstowcs 3 ,
168.Xr setlocale 3
169.\" ----------------------------------------------------------------------
170.Sh STANDARDS
171The
172.Fn mbsrtowcs
173function conforms to
174.St -isoC-amd1 .
175The restrict qualifier is added at
176.St -isoC99 .
177